Predominance of affection is the principle according to which the cases are arranged, those in which the brain was most affected being classed together under one section—the cerebral; those in which the lungs were most affected under a second—the thoracic; and those in which the intestines were most affected under a third—the abdominal. In like manner, the individual cases under each section are so placed as to succeed each other, as nearly as possible, in the order of their severity. Before entering into particular details, it may be useful to exhibit a brief outline of the general pathology of fever, shewing, at one view, the general results which are derived from an examination of the collective cases. In this outline the organs in each cavity are noticed in the order of the frequency and extent in which they are found diseased. I. PATHOLOGY OF THE SOLIDS IN FEVER. 1. _External Appearances of the Body after Death._ The skin is always of a more dusky colour than natural; it is sometimes studded with petechiæ, which in bad cases are large and of a deep purple tint, giving to the body a spotted or speckled appearance. Externally the body always appears emaciated, and on removing the skin, the greater portion of the adipose substance is found to be absorbed; what remains of it is of an unhealthy yellow colour. The muscular fibre is remarkably dark, and this dark colour extends, as we shall see immediately, to the internal viscera. 2. _Morbid Appearances in the Head._ Of the membranes of the brain, the arachnoid is the most constantly diseased. It is seldom or never in a healthy condition. It is always either more vascular than natural, or when in this respect unchanged, it is altered in structure, being thickened, opake and milky: when in this latter state, a gelatinous fluid is usually effused beneath it. Not uncommonly, it is united at several points to the membranes above and below it. To the dura mater it very often adheres, particularly at the angles of the hemispheres, or along the course of the longitudinal sinus; and, in these cases, the adhesion is always peculiarly firm at the vertex. The dura mater itself is less constantly changed in appearance, although this membrane also is sometimes more vascular than natural, and frequently it either adheres with preternatural firmness to the skull-cap, or, on the contrary, it is quite detached from it, in consequence of effusion between it and the bones of the cranium. To the pia mater, the arachnoid is also very often adherent at several points: it is seldom that the pia mater is changed in structure, but it is generally preternaturally vascular. In like manner, the theca which encloses the spinal cord is frequently highly vascular, and contains a larger quantity of fluid than natural.